Introduction: By 2050, the international prevalence of Alzheimer’s disease (AD) is expected to triple, resulting in immense healthcare costs and personal effect. In recent years, researchers have identified age-related hearing loss (ARHL) as one of the most prevalent causes in older adults to be associated with the predisposition for mild cognitive impairment (MCI) and AD. However, the relationship between the two remains unclear. Several plausible mechanisms explaining this hearing-cognition relationship have been suggested, such as social isolation, auditory activation, and neurobiological factors. This review seeks to investigate the literature examining the relationship between ARHL and dementia, how ARHL as a modifiable risk factor plays a role in the severity of cognitive decline in the AD and MCI population, and advocate for why further research on this topic is essential to help create a cognitively healthier and more informed older adult population.
Methods: A comprehensive literature review of fifteen peer-reviewed articles was conducted using a predetermined protocol and inclusion criteria, such as keywords and databases. The search was limited to published articles in the English language from 2010 – present.
Results: No associations were found between brain cortical thickness and those with AD and ARHL in comparison to those with SCD where an association was present. A moderate correlation was found between neurobiological factors such as ApoE4 to explain the relationship between AD and ARHL. The use of active hearing aids did not contribute to a cognitive benefit in those with moderate AD and ARHL compared to the use of placebo hearing aids, or after the secondary activation of hearing aids in the placebo group.
Discussion: The literature shows inconclusive results about the mechanism linking ARHL and AD. The pattern of findings did not show consistent results between studies supporting a particular domain to explain the mechanism behind this relationship.
Conclusion: Through conducting this review, a greater understanding and awareness about the role of ARHL as a risk factor of MCI and AD is provided. Ultimately, this is important in individual lifestyle changes to prevent the onset of ARHL, and subsequently dementia in order to live healthier and with higher quality as they age.
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